In this thesis, the topic "Analysis of the Influence of Gas Mixture in MAG-LSC Welding Process of Ni-Alloy on Corrosion Resistance" is discussed. The first part theoretically describes nickel and Ni-alloys, their corrosion resistance, mechanical and chemical properties, applications, classifications, welding, and weldability. The second part describes the experimental analysis of the welded layer of Ni-alloy. In the experimental analysis, the MAG and MAG-LSC welding processes, the selection and development of the experiment plan, the execution of the experiment, and influencing parameters are described, as well as the analysis of the experiment. Two welded layers were produced using the MAG-LSC welding process. The first welded layer was achieved in an atmosphere of protective gas Argon, and the second in an atmosphere of protective gas Varigon (Argon + Helium). Each welded layer was made on a separate workpiece. One sample was taken from each welded layer to test hardness and δ-ferrite content. After cutting, the samples were ground and etched in Adler. Hardness testing was conducted by measuring hardness at nine points on each sample: three points in the base material zone, three in the heat-affected zone, and three in the fusion zone. δ-ferrite content testing was conducted on the surface of the weld in three points. The hardness values and δ-ferrite content at each point are provided in the experimental analysis, along with images illustrating each part of the experimental analysis process.